Electrical supply system indicator



May 31, 1966 R. BERGSMA ELECTRICAL SUPPLY SYSTEM INDICATOR 2Sheets-Sheet 1 Filed Jan. 9, 1963 INVENTOR.

Alli/- 7 May 31, 1966 R. BERGSMA ELECTRICAL SUPPLY SYSTEM INDICATOR 2Sheets-Sheet 2 Filed Jan. 9, 1963 INVENTOR. )7z/a o/ Z' 28757774 UnitedStates Patent 3,254,294 ELECTRICAL SUPPLY SYSTEM INDICATOR RudolphBergsma, Ann Arbor, Mich., assignor to King- Seeley Thermos C0., AnnArbor, Mich., a corporation of Michigan Filed Jan. 9, 1963, Ser. No.250,432 9 Claims. (Cl. 322-99) This invention relates to signalingsystems, and more particularly to signaling systems for indicating theexistence or attainment of a preselected condition in an electricalcircuit.

Primary objects of this invention are to indicate the eX- istence orattainment of a critical or dangerous condition in an electrical circuitby alarm means controlled by a pair of contacts that are operativelyassociated with first condition responsive means which tend to close thecontacts when a first predetermined condition exists in the circuit andsecond condition responsive means operatively associated with thecontacts to compensate for said contact closing tendency of said firstcondition responsive means until a second predetermined condition occursin the circuit; and to indicate such a critical or dangerous conditionby means including such a pair of contacts which are controlled by suchfirst and second condition responsive means which are furthercharacterized by the ability to maintain said contacts closed for apredetermined period when the electrical circuit is first energized inorder to show that the signaling system is in proper working order.

The nature of the invention and its objects and features will becomemore apparent from a consideration of the following detailed descriptionof the invention when read with reference to the accompanying drawings,in which:

FIGURE 1 is a diagrammatic view of an electrical circuit including oneembodiment 'of the signaling system of the present invention;

FIGURE 2 is a top plan view of a combined signal relay and voltageregulator device constructed in accordance with certain of theprinciples of the present invention;

FIGURE 3 is a view in vertical section taken substantially along theline 33 of FIGURE 2 looking in the direction of the arrows;

FIGURE 4 is a view in vertical section taken substantially along theline 44 of FIGURE 2 looking in the direction of the arrows;

FIGURE 5 is a bottom plan view of the device illustrated in FIGURE 2.

Referring now to the drawings, and electrical circuit is illustrated inFIGURE 1 which includes a signal relay 12 and a voltage regulator 14 forcontrolling a voltage supply system for an automobile or the like of thetype having a voltage generating device .16, a battery 18, and a switch20 which may, for example, be the ignition switch of an automobile. Thevoltage regulator 14, in accordance with conventional automativepractice, serves to maintain the voltage of the battery 18 betweenlimits which are acceptable for many vehicle requirements and includesterminals T T and T for electrically connecting it in circuit with thebattery 18 and voltage generating device 16. The voltage regulator 14 isrepresentatively illustrated in the structural views as a regulator ofthe type having three stages of operation produced by electrothermallyresponsive means as more fully disclosed in the copending United Statesapplication No. 218,412, filed August 21, 1962, of Ernest L. Klavitter,for Voltage Regulator. It will be understood from the followingdiscussion that the signaling system of the present invention is equallysuited for use with other regulators which are responsive to conditionsin an electrical circuit.

3,254,294 Patented May 31, 1966 ICC The voltage generating device 16more particularly includes an armature 22 and a field coil 24 which areelectrically connected to the terminals T and T of the voltage regulator14, respectively. The battery 18 is connected by a conductor 25 and theswitch 20 to the ter minal T Both the generating device 16 and batteryhave a load 26 connected thereacross such as the lights, instruments orother electrical circuits of an automobile or the like. The battery Y18and the voltage generating device 16 are thereby interconnected in aconventional fashion so that either source of potential may supply therequirements of the load 26. The sources of potential, in elfect, floaton the same. lines so that the battery 18 will be charged by the voltagegenerating device 16 so long as the voltage output therefrom is greaterthan the voltage across the battery terminals. Conventional cutoutswitch means (not shown) may be included in the circuit in aconventional manner to prevent discharge of the battery 18 through thearmature 22 of the device 16 when the switch 20 is closed and an engineor the like driving the device 16 is not running.

The signal relay 12 includes a pair of contacts 28, 30, which control alamp 32 or other suitable signaling device which may be disposed on thedashboard or any other convenient place in a vehicle within the visionor other perception of the vehicle operator. to indicate when apredetermined critical or dangerous condition is present in theelectrical system 10. The lamp 32, more specifically, is electricallyconnectedto the relay 12 by means of a terminal T The signal relay .12,more particularly, includes a U- shaped polymetallic element 36 having afirst leg portion 38 anchored at one end thereof by suitable fixedsupport means representatively illustrated, by the grounding symbol 40which does not connote electrical grounding and a second leg portion 42which has one end thereof connected to the opposite end of the first legportion 38 by means of a crosspiece 44 which includes an upright flangeportion 46 which is provided to increase the stiffness of the crosspiece44 to the point where it will not deflect to any significant degree inresponse to the mechanical or thermal forces to which the unit issubjected. The freely movable end of the second leg portion 42 carriesthe contact 2-8 which is mechanically and electrically integraltherewith relative to the contact 30 which is mechanically andelectrically connected to a movable arm portion 48 of electricallyconductive material which is controlled by the voltage regulator 14 in amanner which will be discussed in greater detail subsequently.

The leg portions 38, 42 of the polymetallic element 36 are locatedsubstantially in a common plane when they are at the same temperature.The relay 12, however, includes means for differentially heating suchleg portions to cause the freely movable end of the second leg portion42 to deflect out of such a common plane.

Differential heating of the leg portions 40, 42 is accomplished, moreparticularly, by heating means in the form of a heater winding :50representatively disposed in heat transfer relationship with the secondleg portion 42 and, more particularly, coiled around that leg portion.One end of the heater winding 50 is electrically connected to theconductor 25 and the other end thereof is connected to ground. .As aresult, when the ignition switch 20 is closed, the heater winding 50 isconnected across the battery 18 and the voltage generating device :16 sothat current flows therethrough when the device 16 is operative. Theresultant heating of the second leg portion 42 causes the freelymovable, contact-carrying end thereof to deflectin a direction toseparate the pair of contacts28, 30.

It will'be appreciated that the provision of a U-shaped polymetallicelement 36 of the nature shown will permit compensation of ambienttemperature variations since the effect upon the position of the freelymovable end of the second leg portion 42 of heating of the first legportion 38 is the opposite of that produced by equal heating of thesecond leg portion 42.

As will be discussed in greater detail when the structural views aredescribed, the voltage regulator 14 includes means for electricallyconnecting the arm portion 48 thereof to the conductor 25. Thus, whenthe contacts 28, 30 are closed, current passes through a circuitcomprising battery 18, switch 20, conductor 25, the voltage regulator14, the closed contacts 28, 30, the body of the polymetallic element 36,lamp 32, and suitable conductor means to ground to light the lamp 32 andthereby indicate a critical condition in the system.

In the structural views, illustrating a preferred construction of asignal relay and voltage regulator device adapted to be associated witha voltage supply system such as that illustrated in FIGURE 1, the deviceis mounted on a base 52 of suitable electrical insulating material andincludes a first electrical contact 54 secured to a strip 56 ofelectrically conductive material which is in spaced parallelism andgenerally transverse to a recessed surface 58 on one face of the base 52adjacent one end thereof. One end of the strip 56 is mechanicallysecured to the base 52 by means of a rivet 60 which also electricallyconnects the contact 54 and the strip 56 to the terminal T, whichconnects the device to the battery 18 as discussed above.

The opposite end of the conductive strip 56 is adjustably movable withrespect to the base 52 by means of a threaded screw 64 in threadedengagement with the base 52 which has one end thereof directed throughthe base into engagement with a resilient bumper element 66 of suitableelectrical insulating material which is secured to the opposite end ofthe strip 56.

A second contact 68 is carried on a strip of conductive material 70which is in spaced parallelism with the strip 56 and supported on therecessed surface 58 of the base 52 by means of a rivet 72 which isdirected through the base 52 to electrically connect the strip 70 to theterminal T which is adapted to be connected to ground.

In the preferred construction, a movable contact 76 is locatedintermediate the contacts 54, 68 on the freely movable end of anelongated cantilevered spring arm 78 which has the opposite end thereofanchored to the base 52 by suitable fastening means such as a transversebar 79 which is held against the spring arm 78 by a rivet 80 or thelike. The spring arm 78 is also electrically connected to the terminal Tof the device by means of a suitable electrically conductive elementwhich is representatively illustrated as a rivet 82 which secures theterminal T on one face of the base 52. A pair of laterally spacedelongated spring arms 88, 90 extend longitudinally from the anchored endof the spring arm 78 and on either side thereof to a point adjacent'thefreely movable end of the spring arm 78 where they are interconnected bymeans of a transverse arm 92 and joined to a base portion 98 of aconnector element 100. The elongated spring arms 88, 90 and the springarm 78 are all spring-biased toward the connector element 100 which actsto space the spring arm 78 a predetermined distance from the spring arms88, 90.

Furthermore, the cantilevered spring arm 78 is operatively connected toand controlled by an electrothermal actuator which is representativelyillustrated as a wire 86 which has appropriate electrothermalcharacteristics including a finite resistance and a high coeflicient ofthermal expansion. More specifically, in the preferred embodiment, thewire 86 is representatively illustrated as comprising a single'long wirewhich is wound to define a plurality of reaches, representatively fourin number, which extend substantially parallel to the recessed surface58 of the base 52. One end of the wire 86 connects to 7 one end of ananchor post 104 having the opposite end thereof secured to the base 52.The wire extends therefrom longitudinally of the base 52 to theconnector element where it is wound around an outwardly directed earportion 106 thereof from whence it returns to the opposite end of thebase 52 where it is wound around the outer circumferential surface of anut 108 which is rotatably and eccentrically mounted on one end of apost 110 which has its opposite end directed through base 52 where it issecured to a terminal 112 by means of a snap ring 114.

The wire 86 is directed from the adjusting nut 108 lon gitudinally ofthe base 52 to the connector element 100 where it is wound around asecond outwardly directed ear portion 116 thereof which is spacedlaterally of the first ear portion 106. The wire then returns to theopposite end of the base 52 where it connects to one end of an anchorpost 118 which has the opposite end secured to the base 52.

In the preferred embodiment, the wire 86 is electrically connected tothe terminal T by means of an insulated conductor 120 which has one endthereof electrically connected to the rivet 60 and the opposite endthereof electrically connected to the terminal 112. An elongated stripof conductive material 122 is located on the opposite face of the base52 and has one end thereof electrically connected to the rivet 72 andthe opposite end thereof electrically connected to the pair of spacedanchor posts 104, 118 by means of a transverse arm portion 124.

Hence, when the regulator 14 is connected in a system such as thevoltage supply system illustrated in FIGURE 1, current will pass throughterminal T conductor 120, adjusting nut 108, wire 86, conductive strips124, 122, rivet 72, and thence to the grounding'terminal T The wire 86will accordingly elongate between the anchor points defined by theconnector element 100 and the anchor posts 118, 104 to allow thecantilevered spring arm 78 to move the contact 76 with respect to thefirst and second fixed contacts 54, 68.

In the preferred embodiment, a voltage divider 126 including resistorelements 128, 130 is mounted on the face of the base 52 opposite theface having the recessed surface 58. More specifically, the firstresistor element 128 has one end thereof electrically connected to theterminal T and the opposite end thereof connected to the terminal T atthe rivet 82. Intermediate the terminals T T the resistor element 128 iswound on an elongated strip of insulating material 132 which is directedsubstantially longitudinally of the base 52 with the opposite endsthereof connected to the rivet 60 and the rivet 84, respectively.

The resistor 130 of the voltage divider 126 has the opposite endsthereof electrically connected'between the terminal T and the terminal Tand is wound intermediately thereof on an elongated strip of insulatingmaterial 134 which has the opposite ends thereof connected to the rivet72 and the rivet 82, respectively. Such an arrangement enables ambientair to circulate completely around each of the resistor elements of thevoltage divider 126 so that heat generated thereby will be dissipated bythe surrounding air to prevent an undesirable temperature increase inthe regulator 14.

When the preferred construction is included in an electrical system ofthe type illustrated in FIGURE 1, and the voltage applied across thewire 86 is less than a first predetermined voltage, wire 86 will not beheated sufficiently to permit separation of the contacts 54, 76. Underthis condition the field coil 24 is energized to the maximum extent viaa load or output circuit including battery 18, switch 20, conductor 25,terminal T closed contacts 54, 76, spring arm 78, terminal T and coil 24to ground. It will be observed that under this condition the resistorelement 128 is rendered ineffective by the contacts 54, 76 and theresistor element 130 shunts the coil 24. Accordingly, the generator 16will then develop its maximum output voltage (for its then drivenspeed).

When the voltage output of the generator 16 is between the firstpredetermined voltage and a second predetermined voltage the contacts54, 76 begin to pulse in a cyclic fashion. When the voltage appliedacross the wire 86 exceeds the first predetermined voltage level, theWire 86 Will elongate between the anchored ends thereof until the springarm 78' causes the movable contact 76 to separate from the contact 54.This renders the resistor 128 effective and thereby reduces the voltageacross coil 24 so that the voltage output of device 16 falls. Thisreduces the voltage applied across wire 86 causing it to contract andclose the contacts 54, 76.

In cases in which the voltage output of the device 16 reaches a. valueabove the second predetermined Voltage (but less than a thirdpredetermined voltage) which characterizes a combination of operatingconditions which are most frequently present in a given electricalsystem of this type, the wire 86 will elongate between the anchored endsthereof and hold the movable contact 76 between the contacts 54, 68.

When the voltage output of the device 16 attains or exceeds the thirdpredetermined voltage, the wire 86 will elongate still further to causethe movable contact 76 to engage the contact 68 in a cyclic fashion toshort out the voltage producing device to prevent overcharging of thebattery 18.

Each of the aforesaid stages of regulator operation are morespecifically discussed in the above mentioned copending application ofOtto et al. for Voltage Regulator, the disclosure of which is herebyincorporated by reference as fully as if that disclosure had beenexplicitly disclosed herein.

In the preferred construction, the signal relay 12 is operativelyassociated with the voltage regulator 14 as follows. The polymetallicelement 36 of the signal relay 12 has the first leg portion 38 thereofanchored on the base 52 by means of suitable fastening means such as arivet 136 and has the freely movable end of 'the second leg portion 42located adjacent the crossarm 92 which interconnects the spring arms 88,90. The rivet 136 also electrically connects the element 36 to theterminal T; which is secured by the rivet 136 on the opposite face ofthe base 52. p

The transverse arm 92 (which corresponds to the movable arm portion 48in FIGURE 1) has the contact 30e1ectrically and mechanically integraltherewith. The heater winding 50 of the signal relay 12 one end thereofconnected to a terminal 138 and the opposite end thereof connected to aterminal 140. The terminals 138, 140 are adapted to be electricallyconnected across the voltage producing device'16 so that a component ofthe cur- I rent output of the device Will pass therethrough causing thetemperature of the second leg portion 42 to increase and thereby deflectthe leg in a direction to separate the contact 28 from the contact 30.

The signal relay and voltage regulator device, in accordance withcertain of the principles of the present invention has time delaycharacteristics which enable a signaling device such as the lamp 32 tobe tested. Such testing occurs in the illustrated arrangement when theignition switch is initially closed. At this point the voltagegenerating device 16 is ineffective and the wire 86 is accordinglydeenergized and contracted between the anchored ends thereof causing thecontacts 54,76 to be in engagement. The contracted wire 86 will alsohave moved the elongated spring arms 88, 90 in a direction to cause thecontact 30 on the transverse arm 92 to engage the contact 28 on thepolymetallic element 36. Accordingly, current will pass from the battery18 through the terminal T rivet 60, conductor strip 56, closed contacts68, 76, spring arm 78, spring arms 88, 90, closed contacts 28, 30 andthence through polymetallic element 34, terminal T and lamp 32 toground. The lamp 32 will thereby light.

During normal operation of the voltage supply system, the voltagegenerating device 16 will produce a voltage across the wire 86 whichwill cause it to elongate sufficiently to allow the spring arms 88, 90to separate the operative contacts 28, 30 of the'signal relay 12. Suchseparation will be delayed a preselected time period following closureof the switch 20 (the testing period) and Will thereafter causedeenergization of the lamp 32. Under normal conditions the lamp 32 willnot relight following the lamp testing period.

Under abnormal operating conditions the voltage imposed across the wire86 is sometimes reduced to a point which will cause the Wire to contractbetween the anchored ends thereof sufiiciently to cause the spring arms88, 90 to be deflected in a direction which will tend to move thecontacts 28, 30 into engagement. Such an abnormal condition might, forexample, occur in the illustrated system when an extremely large load isimposed across the voltage generating device 16 during periods in whichthe device 16 is driven at relatively low speeds. During such operationthe contacts 28, 30 of the signal relay 12 would close to energize thelamp 32 to give a false indication of a dangerous or critical condition(such as failure of the generating device 16) except for the presence ofthe polymetallic element 36 and heater winding 50.

The heater winding 50 on the second leg portion 42 of the polymetallicelement 36 will prevent a false indication of such a dangerous orcritical condition since it will carry a component of the current outputof the voltage generating device 16 during such abnormal loadconditions. Accordingly, the second leg portion 42 will be heated todeflect in a direction to maintain the operative contacts 28, 30 of thesignal relay 12 open so long as the voltage generating device 16continues to function.

FIGURES 3 and 4 show the components of the signal relay 12 and thevoltage regulator 14 in the positions assumed under such abnormaloperating conditions and hence the second leg portion 42 of the signalrelay 12 is deflected in a direction to separate the contact 28 from thecontact 30, and the contacts 76 and 54 of the voltage regulator are heldin engagement by the wire 86 acting through the connector element andthe spring arm 78.

When there is a critical condition present in the voltage supply system,for example, when there is no output from the voltage generating device16 because of failure thereof, there will no longer be a currentcomponent passing through the heater winding 50 and hence the second legportion 42 of the signal relay 12 will cool and deflect in a directionto cause the contact 28 mounted thereon to engage the contact 30 of thevoltage regulator 14 and thereby complete a circuit from the battery 18through ignition switch 20, conductor 25, voltage regulator 14, closedcontacts 28, 30, the body of the polymetallic element 36, lamp 32, andsuitable conductor means to ground causing the lamp 32 to light andthereby indicate that the critical condition is present in the system.

The improved signal relay and voltage regulator device, accordingly,will initially indicate whether the signaling system is operative whenthe ignition switch in a voltage supply system of an automobile or thelike is initially closed and will thereafter function to maintain asignaling device such as the lamp 32 in a deenergized stateduring bothnormal and abnormal load conditions and will only be energized when adangerous or critical condition corresponding to failure of the voltageoutput device occurs in the electrical system.

While it will be apparent that the embodiment of the invention hereindisclosed is well calculated to fulfill the objects of the invention, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

What is claimed is:

1. A signaling system for indicating a condition in a voltage supplysystem of the type including a voltage generating device and a voltageregulating means for controlling the voltage generating device,comprising a movable contact arm controlled by the voltage regulatingmeans, signaling means, and signal relay means controlling saidsignaling means and including a pair of electrical contacts, one of saidelectrical contacts being controlled by the movable contact arm of thevoltage regulating means, said signal relay means further includingmeans responsive to the fluctuations of the voltage supply system forcontrolling the other one of said electrical contacts.

2. The combination of claim 1 in which a switch controls the actuationof the voltage supply system and in which said signal relay is eflectiveupon actuation of the switch to operate said signaling means for aninterval demonstrating the operability of said signaling means and forterminating the operation of said signaling means after said interval.

3. A signaling system for indicating a condition in a voltage supplysystem of the type including a voltage generating device and a voltageregulating means for controlling the voltage generating device,comprising a movable contact arm controlled by the voltage regulatingmeans, signaling means, and signal relay means controlling saidsignaling means and including a pair of electrical contacts, one of saidelectrical contacts being cont-rolled by the movable contact arm of thevoltage regulating means, said signal relay means further includingelectrothermally responsive means responsive to the fluctuations of thevoltage supply system for controlling the other one of said electricalcontacts.

4. The combination of claim 3 in which said thermally responsive meansmoves said other contact away from said one contact in response to anincrease of the system voltage. v

5. The combination of claim 3 in which the movable contact arm moves ina direction to tend to close said contacts in response to a reduction inthe system voltage and in which said thermally responsive meanscompensates for the contact closing tendency of the movable contact armuntil a critical condition is present in the voltage supply system.

6. The combination of claim 5 in which the movable contact arm movessaid one contact to a preselected position when the voltage of thevoltage supply system falls to a preselected value below a normal value,and in which said thermally responsive means holds said other contactsubstantially spaced from said one contact when the voltage of thevoltage supply system is normal and slowly moves said other contacttowards said one contact when the voltage of the voltage supply systemfalls to said preselected value.

7. A signaling system for indicating a condition in a voltage supplysystem of the type including a voltage generating device and a voltageregulating means for controlling the voltage generating device,comprising a movable contact arm controlled by the voltage regulatingmeans, signaling means, and signal relay means controlling saidsignaling means and including a pair of electrical contacts, one of saidelectrical contacts being controlled by the movable contact arm of thevoltage regulating means, said signal relay means further including anelectro-thermally responsive means responsive to the fluctuations of thevoltage supply system for controlling the other one of said electricalcontacts, said thermally responsive means including a polymetallicelement having a freely movable end portion controlling the other one ofsaid contacts and heating means therefor electrically connected to thevoltage generating device for heating said polymetallic element inaccordance with the output from the voltage generating device.

' 8. The combination of claim 7 in which aswitch controls the actuationof the voltage supply system and in which said signal relay is effectiveupon actuation of the switch to operate said signaling means for aninterval demonstrating the operability of said signaling means and forterminating the operation of said signaling means after said interval.

9. The combination of claim 7 in which the movable contact arm movessaid one contact to a preselected position when the voltage of thevoltage supply system falls to a preselected value below the normalvalue, in which said heating means heats said polymetallic element whenReferences Cited by the Examiner UNITED STATES PATENTS 2,064,460 12/1936Carr et a1 340-220 2,511,631 6/1950 Gordon 340220 2,833,889 5/1958 Boddy200-122 3,022,456 2/1962 Larson et a1 320-48 X NEIL C. READ, PrimaryExaminer.

R. M. ANGUS, Assistant Examiner.

1. A SIGNALING SYSTEM FOR INDICATING A CONDITION IN A VOLTAGE SUPPLYSYSTEM OF THE TYPE INCLUDING A VOLTAGE GENERATING DEVICE AND A VOLTAGEREGULATING MEANS FOR CONTROLLING THE VOLTAGE GENERATING DEVICE,COMPRISING A MOVABLE CONTACT ARM CONTROLLED BY THE VOLTAGE REGULATINGMEANS, SIGNALING MEANS, AND SIGNAL RELAY MEANS CONTROLLING SAIDSIGNALING MEANS AND INCLUDING A PAIR OF ELECTRICAL